Petrogenesis and Solidification Depth of the Jurassic Daebo and Cretaceous Bulguksa Granitic Rocks in South Korea
Petrogenesis and Solidification Depth of the Jurassic Daebo and Cretaceous Bulguksa Granitic Rocks in South Korea
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DOI：
10.1111/j.1751-3928.2012.00195.x
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发表时间：
2012-07
期刊：
影响因子：
1.4
通讯作者：
E. Uchida;S. Choi;Daisuke Baba;Y. Wakisaka
中科院分区：
文献类型：
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作者：
E. Uchida;S. Choi;Daisuke Baba;Y. Wakisaka
我们研究了韩国侏罗纪大宝和白垩纪佛国沙花岗岩。前者主要分布在京畿和岭南地块，后者主要分布在庆山盆地和Ogcheon带。大宝花岗岩体一般为钛铁矿系列，属I ~ S型。这些岩石与Au-Ag热液矿床有关，而Bulguksa花岗质岩石为磁铁矿系列和I型，与Pb-Zn、Cu和Mo-W热液矿床以及Au-Ag热液矿床有关。大田花岗质岩石在化学成分上具有绿质特征。它们被认为是由于较厚的下大陆地壳部分熔融而产生的。相反，庆山盆地的Bulguksa花岗质岩石是非埃达克质，被认为是由地幔楔块的部分熔融形成的。大宝花岗质岩浆岩的岩浆形成阶段相对较浅，但与佛国沙花岗质岩浆岩相比，岩浆在深部凝固。乌川带中西部的佛国沙花岗质岩石被认为是由大陆地壳部分熔融的岩浆分馏形成的。花岗岩中黑云母和角闪石的总铝含量增加，表现为：庆山盆地的佛国沙花岗岩<乌川带和京畿、岭南地块的佛国沙花岗岩>乌川带的大宝花岗岩>京畿、岭南地块的大宝花岗岩。这个顺序对应于凝固深度的增加。
We investigated the Jurassic Daebo and Cretaceous Bulguksa granitic rocks in South Korea. The former are distributed mainly in the Gyeonggi and Yeongnam massifs and the latter are present in the Gyeongsan basin and Ogcheon belt. The Daebo granitic rocks generally are of ilmenite series and I to S type. These rocks are associated with Au–Ag hydrothermal deposits, whereas the Bulguksa granitic rocks are of magnetite series and I type, and are associated with Pb–Zn, Cu and Mo–W hydrothermal deposits, as well as Au–Ag hydrothermal deposits. The Daebo granitic rocks show adakitic signatures in their chemical compositions. They are considered to have been derived from partial melting of the thick lower continental crust. Conversely, the Bulguksa granitic rocks in the Gyeongsan basin are non‐adakitic and are considered to have been derived from partial melting of a mantle wedge. Magmas of the Daebo granitic rocks formed at relatively shallow levels, but solidified at deep levels compared with those of the Bulguksa granitic rocks. The Bulguksa granitic rocks in the central to western Ogcheon belt are considered to have been formed by fractionation of magmas derived from partial melting of continental crust. The total Al contents of biotite and hornblende in the granitic rocks increased, with the Bulguksa granitic rocks in the Gyeongsan basin < the Bulguksa granitic rocks in the Ogcheon belt and Gyeonggi and Yeongnam massifs and the Daebo granitic rocks in the Ogcheon belt < the Daebo granitic rocks in the Gyeonggi and Yeongnam massifs. This order corresponds to an increase in solidification depth.